Illuminating instrument.



H. T. MARTIN & J. P. GOLDEN. ILLUMINATING INSTRUMENT. APPLICATION FILED NOV. 30, 1910.

1,01 1,980. Patented Dec. 19, 1911.

Harvard Zulu/fin v J/IIEJ Gd/t/en. IVITNESSES- LVVENTORJ:-

ATTORNEY.

HOWARD T. M ABTIN AND JAMES GOLDEN, OF BALTIMORE, MARYLAND.

ILLUMINATING INSTRUMENT.

Specification of Iietters Patent. Patented Dec, 19, 1911.

Application filed November 30, 1910. Serial No. 594,954.

To all whom it concern:

Be it known that we, HOWARD T. MARTIN and JAMES F. GOLDEN, citizens of the United States, residing at Baltimore, in the State of. Maryland, have invented certain new and useful Improvements in Illuminating Instruments, of which the following is a specification.

This invention is an electric minator particularly adapted and intended for dental or surgical use in inspecting the interior of the mouth, throat and the other cavities of the body, but capable of other uses if desired.

The invention is especially an improvement on the illuminating instrument shown and described in our application No. 534,927 filed Dec. 27, 1909. The object of the present invention is to remedy certain defects found in the con struct'ion disclosed in the former application, above referred to, and to generally improveand simplify the parts, special objects being to prevent the breakage of the lamp bulb and glass tube inclosingthe same, and to improve the electrical connection to pret ent burning out of the lamp.

The invention is illustrated in the accompanying drawings in whichj Figure 1 is a longitudinal sectional view ofvthe instrument, the electricalconnections being shown in diagram. Fig. 2 isa side view in detail of the end of the tube which holds the lamp. Fig. 3 is an end view of the tube as shown in F1 2.

Referring specifica ly to the drawings, the

- handle part of the casing of the instrument comprises three sections, a front end section 6, an intermediate section 7 and a rear section 8, these sections being made of hard rubber or other suitable material and united by threaded joints. The casing of the front part of the instrument consists of a glass tube 9 closed at its front end and held at its rear end within the casing section 6 in which itfits, the rear end of the tube bein -flanged as at 10 to engage behind a shoul er 12 in the tubes 6. In case of breakage of the tube it can be -uickly renewed by unscrewing the part 6 an slipping the tube out rearwardly.

ithin the casing thus formed is a metal tube 13 having an external shoulder 14 which rests against a packing ring 11 between said shoulder and theflange of the glass tube 9. v

' Within the tube 13 is an insulating core lamp or illu closes a rod 25 which extends throu h a 20 which has .near its rear edge a shoulder 21 which serves to separate the tube 13 from a rearnmetal tube 22 which'corresponds in size and position to the tube 13, and the tubes 13 and 22 may be electrically connected by a sliding switch 23 which has a finger piece 24 pro ecting through a slot in the c'asing. The lamp circuit is opened and closed this switch. 4 The insulating core 20 inbore in said core and projects at the out end thereof to contact with the lamp socket 26, the bulb being indicated at 27, the inner or central terminal of the lamp being in contact with the front end of the rod 25 and the outer or sleevecontact of the lamp being in conducting engagement with the tube 13. The lamp is held 1n this position by a special construction-of the end of the tube 13. The

front end ofsaid tubeis cut away on one side, to the edge 28, against which the lamp rests,

less than half the circumference'of the tube,

leaving a part 29 of slightly more than half the circumference,

the longitudinal line of out being on a slight angle, as indicated by the dotted line 30'. This forms two wings or sides, and the tube being made of spring metal, the lamp may be sprung in between the opposite sides or wings of the part 29 which clamp the same and thereby hold the lamp in position. The rod 25 is movable, being pressed behind by a spring 31, and when the lamp is inserted the spring is slightly compressed by the pressure on the rod, and this acts to press the lamp against the wings of the part 29 so that it will not rattle-or loosen accidentally. There is therefore no pressure on the end of the outer glass tubev 9 against the lamp bulb, and although the-parts may be so arranged that the bulb and tube will be in contact at the front end, there is no such pressure as would tend to break the bulb or force out the end of the tube 9, as sometimes happened in the former construction in which the lamp was held in place by the pressure of the outer tube against its bulb.

The tube 13 is connected by a rod 33 a leading in wire 34 connected to one terminal of a rheostat 35 the other terminal of which is connected to a supply wire 36, and also by a wire 37 to a screw 38 in electrical connection through spring 31 to the rod 20. The other supply wire 38 1 rear: tube 22.-

the cutaway portion being somewhat s connected to the o When the movable, member ofthe rheostat is on the point to which the wire 36 is connected, the resistance is cut out, and

switch 23 being closed, the full amount of current will be carried by the wire 38 through the switch to. rod 33 and wire 34, and thence to wire 36, thus completing a direct return circuit, and allowing no current to pass through the lamp. When the resistance is out in at the rheostat, by shifting its movable member, a part of the current passes through the lamp, and part also through the direct; return, the relative amounts being proportionate to the amount of resistance cut in. When the switch 24 is open,'all the current is cut oil from." both the rheostat and the lamp. The lamp can be connected to' a battery if desired, by disconnection from the rheostat, and connecting the wires 38 and 37 to a battery; or wire 34 can simply be disconnected from the 'rhe'ostat 'to produce a straight series lamp. When the switch is closed the circuit is through the wire 38, sleeve 22, switch 23,

tube 13, to the lamp, and back through the rod 25, screw 38*, and wires 37 and 36, part of the current also passing back 'from the tube 13 through rod 33, w1re 34 and rheostat 35, which is thus in a shunt circuit, and by the manipulation of the rheostat the amount of current assing through the filament of the lamp is controlled and can be varied according to the voltage of the lamp,

therebglllenabling the use of a small lamp on the or ary electric light'circuit, and avoidingburning put of the lamp. As the resistance is cut m, a proportionally increasing amount of current passes through the lamp,

until its illumination is eliected. When the switch 23 is opened the lamp and rheostat circuits are also opened.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is 1. The combination of an electric lamp,

'andco'nducting connections to the lamp, in-

cluding a tube with a recess at the end in which the lamp fits, and a rod pressing against the lamp to hold it in said recess.

2. The combination of an electric lamp, a conducting member having wings engaging the lamp, and a spring-pressed conducting member, located behind the lamp and pressing the same to engagement with the wings to hold it in position.

3'. The combination of an electric lamp, a

conducting tube recessed on one side at its front end to form opposite wings between which the lamp fits and is held, and a sprin pressed conducting rod insulated from said tube and pressing against the rear endof the lamp to hold it betweensaid wings.

4. The combination of an electric lamp, a central conductor rod 'bearin against the rear end of the base of the amp,.another conductor having rojections en ging the front end of the amp base, an a spring pressing the rod against said base to hold it against said projections.

In testimony whereof, we afiix our signatures in presence of two witnesses.

' HOWARD T. MARTIN. JAMES F. GOLDEN. Witnesses:

ALnx SLAsMAN, EMMA S. GOLDEN. 

